U.S. patent number 4,490,139 [Application Number 06/461,912] was granted by the patent office on 1984-12-25 for implant needle and method.
This patent grant is currently assigned to Eli Lilly and Company. Invention is credited to John R. Huizenga, Lloyd E. Reddix.
United States Patent |
4,490,139 |
Huizenga , et al. |
December 25, 1984 |
Implant needle and method
Abstract
An improved subcutaneous implant needle is formed as a hollow
tube having its forward end cut on a plane at an acute angle to the
central axis of the tube to form an elliptical opening, and an
elliptical outer edge having a sharp forward portion. The forward
extremity of the needle is dressed to form cutting edges
intersecting at an obtuse angle and forming a central point. The
dressed edges have a width preferably less than two-thirds the
diameter of the tube, and the adjoining side portions of the
elliptical outer edge are rendered unsharp and dulled, as by
abrasion such as sandblasting or tumbling in abrasive media. The
needle is dimpled at two locations closely adjacent the rear of the
opening.
Inventors: |
Huizenga; John R. (Mooresville,
IN), Reddix; Lloyd E. (Indianapolis, IN) |
Assignee: |
Eli Lilly and Company
(Indianapolis, IN)
|
Family
ID: |
23834442 |
Appl.
No.: |
06/461,912 |
Filed: |
January 28, 1983 |
Current U.S.
Class: |
604/57; 604/264;
604/272 |
Current CPC
Class: |
A61B
17/3417 (20130101); A61M 37/0069 (20130101); A61B
17/3468 (20130101); A61M 5/3286 (20130101) |
Current International
Class: |
A61B
17/34 (20060101); A61M 5/32 (20060101); A61M
005/00 () |
Field of
Search: |
;604/57-64,264,272-274 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pellegrino; Stephen C.
Attorney, Agent or Firm: Barnes & Thornburg
Claims
What is claimed is:
1. A subcutaneous implant needle for flexible implant pellets
comprising a hollow metal tube having an outer diameter of a
significant fraction of an inch and of sufficient rigidity to
resist bending when subjected to manual force,
one end of the tube being cut on a plane at an angle less than
30.degree. with respect to the central axis of the tube to define
an end face surrounding an elliptical opening and having an
elliptical outer edge, said end being provided with a pair of
dimples, one located a fraction of an inch forward of the rear edge
of the opening and the other located a fraction of an inch behind
the opening.
2. A subcutaneous implant needle comprising a hollow tube formed
from stainless steel having an outside diameter of approximately
1/4 inch (6.35 mm) and an inside diameter of approximately 7/32
inch (5.556 mm) and of sufficient rigidity to resist bending when
subjected to manual force, one end of the tube being cut on a plane
at an angle of from about 15.degree. to about 20.degree. with
respect to the central axis of the tube to define an end face
surrounding an elliptical opening and having an elliptical outer
edge, the forward extremity of the cut portion being dressed to
provide two substantially straight sharpened edge portions having a
total width less than the outside diameter of the tube and forming
an included angle of the order of 135.degree., the one end being
provided with a pair of dimples, one dimple being located in the
wall opposite the opening about 3/16 inch (4.76 mm) forward of the
rear edge of the opening and another dimple being located about
3/16 inch (4.76 mm) rearward of the rear edge of the opening.
3. The subcutaneous implant needle of claim 2 wherein the side
portions of the elliptical outer edge are abraded to blunt their
sharpness.
4. An implant needle as in claim 3 in which the sharpened edge
portions have a total width less than two-thirds the diameter of
the tube.
5. An implant needle as in claim 1 in which the side portions of
the elliptical outer edge of said end face are treated to dull the
sharpness thereof.
6. An implant needle as in claim 5 in which said side edge portions
are abraded to dull their sharpness.
7. An implant needle as in claim 5 in which the needles are
sandblasted to dull the sharpness of said side edge portions.
8. A subcutaneous implant needle comprising a hollow metal tube
having an outer diameter of a significant fraction of an inch and
of sufficient rigidity to resist bending when subjected to manual
force, one end of the tube being cut on a plane at an angle less
than 30.degree. with respect to the central axis of the tube to
define an end face surrounding an elliptical opening and having an
elliptical outer edge, the forward extremity of the cut end being
sharpened over a width less than the diameter of the tube and the
adjacent diverging side portions of the elliptical outer edge being
treated to dull the sharpness thereof, said end also being provided
with a pair of dimples, one located a fraction of an inch forward
of the rear edge of the opening and the other located a fraction of
an inch behind the opening.
9. An implant needle as in claim 8 in which the cut end of the tube
is sandblasted to an extent sufficient to dull the sharpness of the
side portions of the elliptical outer edge of said end face.
10. An implant needle as in claim 9 in which the sandblasting
effect is confined to parts other than said sharpened edge
portions.
11. The method of manufacturing a subcutaneous implant needle
comprising
providing a hollow tube of rigid material having a forward end,
cutting the forward end of the hollow tube along a plane at an
acute angle to its central axis to provide an elongated and closed
outer edge,
dimpling the hollow tube in two locations closely adjacent the rear
edge of the opening, and
abrading the cut end of the needle to blunt the sides of its
elongated and closed outer edge.
12. The method of claim 11 wherein the tube is dimpled in a plane
through the central axis of the tube and on opposite sides of the
axis.
13. The method of manufacturing a subcutaneous implant needle
comprising the steps of providing a hollow tube of rigid material
having a forward end, cutting the forward end of the hollow tube
along a plane at an acute angle to its central axis to provide an
elongated and closed outer edge, dimpling the hollow tube in two
locations closely adjacent the rear edge of the opening, abrading
the cut edge of the needle to blunt the sides of its elongated and
closed outer edge, dressing the foremost extremity of the cut end
of the tube to form a sharp cutting edge thereon of a width less
than the diameter of the tube and performing the abrading step so
as to avoid dulling such sharp cutting edge.
14. The method of claim 13 in which the abrading is done by
sandblasting after the sharpening step and while the sharp cutting
edge is protected from the effect of sandblasting.
Description
This invention relates to an improved needle for placing implants
under the skin of a farm animal and a method of its
manufacture.
Implants have been developed to introduce therapeutic agents into
the body of an animal for providing a uniform release of drugs over
long periods of time. Such implants typically comprise a drug
carrier formed of an organopolysiloxane rubber composition (more
generally known as silicone rubber) which is non-reactive toward
the drug, non-toxic to the body, and known to be compatible with
living tissue even after a prolonged implantation period. The drugs
are included in the composition in powder or semisolid or liquid
form, and generally have appreciable solubility in the polymer
composition of the carrier. The drugs are released from the carrier
into the body of the animal by diffusion or migration
interstitially between the elastomer molecules to the outer surface
of the carrier from which they are removed by the animal's body
fluid.
Such implants are not eroded by the animal's body fluids and permit
the exposure of the animal to the effect of the drug to be
terminated at will by removal of the implant. For example, when the
drug is a growth stimulant, termination of the exposure of the
animal to the effects of the drug permits a livestock owner to
rapidly meet the demands of the marketplace by electing to shorten
the time between the treatment of the animal with the drug and
slaughtering the animal for use.
To provide treatment of animals, for example, with estradiol, and
permit the termination of such treatment, the implants used are in
rod-like form and have lengths on the order of an inch. The
insertion of such implants into the animal's body must frequently
take place at a remote site, such as at a livestock ranch or at
feeder lots in the field, and must be performed by ranch and field
hands frequently under dirty conditions.
Where such implants are used to expose an animal to drugs over a
long period, as in the case of growth stimulants such as estradiol,
it is of course necessary that the implant remain in the body of
the animal. Implants are placed one by one in the animals by
inserting the implant preferably under the skin of the animal's
ear. Frequently, the animals are dipped or otherwise exposed to
liquid materials after the insertion of the implant. Such exposure
to liquid generally results in the animal shaking his head, and
thus imposing forces on the implant tending to displace it from the
animals's ear. Because the animals, after these treatments, are
released into the field, it is not desirable or economically
feasible to check each animal to assure that the implant has
remained in place.
Implants have been inserted under the skin of the animal by hollow
steel tubes or needles having their forward ends cut on a plane
defining an acute angle with the central axis of the tube, thus
forming an elliptical opening surrounded by an elliptical end face
which, along its forward sides and end, form a sharp edge with the
cylindrical outer surface of the tube. The point of the tube or
needle is commonly sharpened to provide an acutely angled point and
a pair of sharpened edges extending outward and rearward of the
point. With the use of such a needle, it has been found that
implants placed subcutaneously in the ear of a farm animal may
become dislodged within a short period of time after their
implantation. It is believed this loss of the implant is aggravated
at least in part by the shaking of the animal's head which seems to
be a natural instinct of the animal following its treatment.
In accordance with the present invention, an implant needle can be
manufactured by providing a hollow tube of rigid material, for
example, stainless steel, grinding the forward end of the hollow
tube along a plane at an acute angle to its central axis to form an
elliptical end face having an elongated and closed outer edge, and
the point can then be honed to provide the sharp point and adjacent
angular sharpened edges. To assist in obtaining positive
implantation of the implants, the tube or needle is dimpled at two
locations closely adjacent the rearward edge of the elliptical end
opening, preferably with one dimple located within the length of
the opening and the other dimple behind the opening. To help reduce
the loss of implants from the animal's body following their
implantation, the foremost extremity or point of the cut end is
desirably honed or otherwise treated to produce two sharpened edges
lying at an obtuse angle and having a total width less than the
outside diameter of the tube, preferably less than two-thirds of
such diameter. The needle is also treated to reduce the sharpness
and blunt the outer edge of the cut end face, especially the
diverging side edges of such face which adjoin and extend rearward
from the honed point. The blunting treatment is desirably by
abrading the side edges, and this may be done by tumbling the
needles with an abrasive media or by sandblasting. When
sandblasting is used, the needles may be held in a support which
covers the honed point and its adjacent angular sharp edges but
exposes the side edges of the elliptical end face, so that the
honed point and angular edges are shielded from the abrasion and
remain sharp.
The accompanying drawing illustrates the invention and shows an
embodiment exemplifying the best mode of carrying out the invention
as presently perceived. In such drawings:
FIG. 1 is a top view of a subcutaneous implant needle in accordance
with the invention;
FIG. 2 is a side view of the needle of FIG. 1; and
FIG. 3 is a bottom view of the needle of FIG. 1.
The needle 10 shown in the drawing is formed from a hollow tube of
rigid material, preferably one such as stainless steel that will
provide a needle of rigid structure and may be easily cleaned and
sterilized, either by immersion in alcohol or by exposure to high
temperature. The tube may have an outer diameter of a significant
fraction of an inch, for example, within a range from about 1/8 of
an inch to about 3/8 of an inch (3.175 to 9.525 mm), and preferably
about 1/4 of an inch (6.35 mm). The wall should have sufficient
thickness to provide enough rigidity that the needle will not bend
in use where it is subjected to the manual force that may be
exerted by a ranch hand. Where the tube is formed of stainless
steel, such rigidity may be obtained with walls having a thickness
of from about 0.010 of an inch to about 0.020 of an inch (0.254 to
0.508 mm).
The forward end 10a of the needle is formed by grinding the hollow
tube along a plane 13 at an acute angle A to the central axis 14 of
the tube, as shown in FIG. 2. The acute angle A is preferably
between about 15.degree. and about 20.degree.. Such grinding
produces an elliptical end face having an elongated elliptical
outer edge 15 and a similar inner edge defining an elliptical
opening 16.
The forward extremity of the thus-ground tube is sharpened, as by
honing over a length of several millimeters, preferably within a
range from about 3 millimeters to about 5 millimeters. The
forwardmost portion of the elliptical outer edge 15 is thus
sharpened to define two substantially straight edge portions 15a
and 15b that intersect at an obtuse angle B, preferably on the
order of 120.degree. to 135.degree.. The overall width of the
sharpened edge portions is less than the outside diameter of the
tube and on a 1/4 inch (6.35 mm) needle is preferably about 4
millimeters, and such edge portions extend rearwardly of their
point of intersection a distance of about 1.6 millimeters.
After formation of the sharp cutting edges 15a and 15b, the forward
end 10a of the needle is treated to remove the sharpness from and
blunt the elliptical outer edge 15 of that end, especially along
the diverging side edges adjoining the cutting edges 15a and 15b.
One manner of rendering edge 15 unsharp is by sandblasting, and
another manner is by tumbling in ceramic media. In sandblasting,
the needle may be held in a holder which covers the sharpened edges
15a and 15b. The forward end 10a of the needle is othewise exposed
to the sandblasting for a time sufficient to remove material from
the side edge 15 that would otherwise provide a keen edge, and thus
render edge 15 relatively unsharp or blunt. In addition, to further
assist in the controlled implantation of implants into the animal,
the needle is dimpled in two locations. Desirably, the first dimple
17 is located closely behind the opening 16, and the second dimple
18 is located within the area of the opening, rearward of the
approximate center 16a of elliptical opening 16.
Where such subcutaneous implantation needle has an outside diameter
of about 1/4 inch (6.35 mm) and an inside diameter of about 7/32 of
an inch (5.556 mm) and has its forward end cut along a plane 13
having an angle between 15.degree. and 20.degree., the first dimple
17 may be located slightly more than 3/16 inch (4.76 mm) rearward
of the rear edge 16b of the opening 16, and dimple 18 may be
located about 3/16 inch (4.76 mm) forward of the rear edge 16b of
the opening. The dimples are, preferably, located generally in a
plane through the center of the needle and perpendicular to its cut
end face, and extend into the tube a distance of about 0.015 inch
to about 0.030 inch (0.38 mm to 0.76 mm).
The dimples will engage the implants prior to their explusion from
the tube, prevent them from falling from the opening, and permit
their expulsion to be controlled. Because implants may be curved,
the location of the dimples in a plane through the center of the
tube provides the probability of engagement of the ends of the
implant by the dimples.
While this application discloses a specific preferred embodiment,
other embodiments may be devised without departing from the spirit
and scope of the invention as set forth in the following
claims:
* * * * *